Narcissus backend.php Image Configuration Command Injection

Summary

Narcissus is vulnerable to remote code execution via improper input handling in its image configuration workflow. Specifically, the backend.php script fails to sanitize the release parameter before passing it to the configure_image() function. This function invokes PHP’s passthru() with the unsanitized input, allowing attackers to inject arbitrary system commands. Exploitation occurs via a crafted POST request, resulting in command execution under the web server’s context.